The background of the invention is the networking of sensors, for example of one-dimensional or two-dimensional optical code readers or of laser measuring systems, via a digital fieldbus, for example of the type Profibus or DeviceNet. It is known for this purpose to provide the sensors with their own fieldbus interface which permits a connection of the sensor to the fieldbus and communication between the sensor and the fieldbus. A fieldbus interface integrated in the sensor, however, makes the actual sensor module undesirably expensive and undesirably voluminous for some applications. The relevant sensor is moreover admittedly adapted to a specific fieldbus; but the sensor can no longer easily be used for other fieldbus types.
Alternatively to its own fieldbus sensor, it is known to provide the relevant sensor with a connection module which has a sensor interface which permits a connection to a serial interface of the sensor. The connection module is connected to a so-called gateway circuit which translates the data exchanged at the sensor interface of the connection module into the format of the fieldbus and vice versa and which is connected for this purpose via a bus interface to the fieldbus. The connection module and the gateway circuit thus serve for the adaptation of both the hardware (respective interface) and the data formats (bus protocol) between the fieldbus and the sensor, with the gateway circuit usually adapting a serial sensor interface to a specific fieldbus type. To configure the sensor for the fieldbus and to permit communication with the fieldbus, the user must parameterize two devices, namely the sensor and the interposed gateway circuit.
Known connection modules have proven to be insufficient, in particular with optoelectronic sensors, since these have digital switch inputs and outputs in addition to a serial data interface and since additional circuits are therefore required to bring about the desired adaptation to a specific fieldbus. With the known connection modules, the parameterization, i.e. the adaptation of the gateway circuit to the fieldbus addressing and the fieldbus protocol is moreover undesirably complex since two devices (sensor and gateway circuit) have to be addressed.